<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">

    <title>首页</title>
</head>
<body>

<div id="app">

</div>

</body>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
    var myData = {
        a: 1
    }
    var app = new Vue({
        el: '#app',
        data: myData
    })

    console.log(app.a);
    app.a = 2;
    console.log(myData.a);
    myData.a = 4;
    console.log(app.a)
</script>
</html>
